Anyone with welding knowledge?

[SFHGolfTDI]

So I recently had a local hitch welder make a custom hitch for my TDI: http://forums.tdiclub.com/showthread.php?t=441438

I know I'm being picky, but I really don't like where my hitch pin hole ended up, basically overlapping the lower bumper cover. My options are to cut the cover more and forget about it, or to go back and see what they think first (they made me take all my own measurements and responsibility for how it turned out, so they might be unwilling to help out here). The measurement was thrown off during fabrication by a 1/4" plate that they added to the back of the receiver.

My understanding is welding is permanent, and the parts would need to be cut off for any modifications. My question is, how hard is it to grind off or cut at the welds on the receiver and re-weld it after cutting the receiver down 1/2"? Does it take a lot of cutting/grinding, or is it a fairly straightforward job? Also, how destructive is it? I'd like them to reuse the actual receiver since I purchased that separately.

Any insight from welders out there?

 

[Joester]

I do quite a bit of fabrication for my job as a mechanical engineer and as a hobby at home and I would say its going to get messy if they try to cut that off and re-weld it. It is totally possible to grind welds down if you do them wrong but those look like some big welds and some thick metal. Hindsight is 20/20 but next time it might be worth it to just have them tack everything and then do a mock-up install on your car to see if all the dimensions turned out right, followed up by them permanently welding all the seams on the hitch to finish it.

I don't know how much clearance you have behind the bumper cover, but what about some sort of spacer to bring the hitch pin hole out further, instead of behind the cover as originally planned? Not sure if thats possible as I don't fully understand how the hitch mounts to the car.

At this point I think your best bet is to just further clearance the black plastic piece to allow you to get your pin in there.

 

[GreenLantern_TDI]

Yes straight forward. Every time you weld something like that you change the makeup of the steel. Can it be done? Yes. Will it be just as good or strong as it is now? Probably. If i had done this myself i would exhaust my other options before re cutting and welding. I see exactly what ur talking about with the pin hole placement. It blows but youve got the best of both worlds with this hitch. Trim alil more bumper and enjoy. No one but you will notice. You cant win them all. Just incase that didnt answer your as the fabricator id be pist if ya asked me to redo it.

 

[SFHGolfTDI]

I do quite a bit of fabrication for my job as a mechanical engineer and as a hobby at home and I would say its going to get messy if they try to cut that off and re-weld it. It is totally possible to grind welds down if you do them wrong but those look like some big welds and some thick metal.

I don't know how much clearance you have behind the bumper cover, but what about another 3/8" or so of metal between the mounting plates and the car to act as a spacer to bring the hitch pin hole out further, instead of behind the cover as originally planned? Hopefully that makes sense what I'm trying to say.

Thanks for the feedback. I get what you're trying to say, but the hitch is mounted through the frame rails. Holes and weld nuts already installed. So if they were to push the hitch out further, it would not only reduce my clearance (and look funnier), but also they would have to re-drill and put 6 new weldnuts on, and those nuts would be too close to the original ones, creating a new problem. They'd probably have to cut and replace the 1/2" steel through the rails completely. My preference would be to cut the lower valence before I'd have it protrude out more.

So, when a weld is made, how far below the actual bead does it go? If you just grind off the weld and not the metal, can you get the pieces apart? I don't want to cut the hitch apart, just a few welds.

 

[SFHGolfTDI]

Yes straight forward. Every time you weld something like that you change the makeup of the steel. Can it be done? Yes. Will it be just as good or strong as it is now? Probably. If i had done this myself i would exhaust my other options before re cutting and welding. I see exactly what ur talking about with the pin hole placement. It blows but youve got the best of both worlds with this hitch. Trim alil more bumper and enjoy. No one but you will notice. You cant win them all. Just incase that didnt answer your as the fabricator id be pist if ya asked me to redo it.

Yeah, I'm pretty sure he'll be pissed. He was very clear with me that he didn't like to take jobs from "enthusiasts with German cars because it never ends well" for exactly this reason. That's why he made me do all the measuring and planning myself. He wanted little to do with that part of it. But then he also didn't tell me about the 1/4" plate backing until he was already spot welding things into place. He asked if I thought it would be ok, and I wasn't sure because it was so close (as you can see in the pics). I hesitatingly said yes. I could have said no at that point and had him cut some of the receiver off, but it was already a long day. Of course, in hindsight, after putting things back together, I wish I had made him cut it, but I wasn't sure it would be an issue.

I definitely don't expect him to do it for free. I'd be willing to pay him a little more to fix it if it is even possible. But I want to know what I'm getting into to decide whether it is even worth pursuing. Thanks for the feedback.

 

[Joester]

Thanks for the feedback. I get what you're trying to say, but the hitch is mounted through the frame rails. Holes and weld nuts already installed. So if they were to push the hitch out further, it would not only reduce my clearance (and look funnier), but also they would have to re-drill and put 6 new weldnuts on, and those nuts would be too close to the original ones, creating a new problem. They'd probably have to cut and replace the 1/2" steel through the rails completely. My preference would be to cut the lower valence before I'd have it protrude out more.
So, when a weld is made, how far below the actual bead does it go? If you just grind off the weld and not the metal, can you get the pieces apart? I don't want to cut the hitch apart, just a few welds.

For a simple MIG weld like this if you grind the weld off, the parts should pretty much just fall apart.

The difficult part is grinding off just the weld and not any of the original metal pieces. Its a long and not-very-fun process which is why I stand by my original statement that you should just clearance the plastic piece some more and call it a day.

but to answer your question yes it is possible to just grind the welds off and re-position the parts. Just expect an angry machinist and another $75 or more. Its not a "here's $20 to do this real quick" type of job.

 

[waltzconmigo]

SFH---not sure if this would be strong enough to take the vibrations it would take or if it would cause any type of unpleasant noise but what about cutting off a piece of the valance (say four inches) and putting a hinge on there that would push up so you have access to the bolt but would fold down when not in use? (sorry for the run on sentence)

 

[SFHGolfTDI]

For a simple MIG weld like this if you grind the weld off, the parts should pretty much just fall apart.

The difficult part is grinding off just the weld and not any of the original metal pieces. Its a long and not-very-fun process which is why I stand by my original statement that you should just clearance the plastic piece some more and call it a day.

but to answer your question yes it is possible to just grind the welds off and re-position the parts. Just expect an angry machinist and another $75 or more. Its not a "here's $20 to do this real quick" type of job.

As far as structural integrity with pieces being cut, the only pieces that matter are the large cross bar, and the receiver. Otherwise there is just a flat backing 1/4 steel, and their homemade chain loop piece.

I was thinking of offering around $50. Will have to see if this is worth it and how they react. Might try taking some coffee, donuts and my toddler to minimize the discomfort of the ask.

 

[SFHGolfTDI]

SFH---not sure if this would be strong enough to take the vibrations it would take or if it would cause any type of unpleasant noise but what about cutting off a piece of the valance (say four inches) and putting a hinge on there that would push up so you have access to the bolt but would fold down when not in use? (sorry for the run on sentence)

Thanks for the suggestion. It's probably not worth the hassle of a hinge and all that. It might be a lot harder to implement in reality with too many moving pieces.

I keep going back and forth between cutting the valence some more and and forgetting about it, or stopping by the shop and seeing what they have to say (though it could likely be uncomfortable). If I get a clear no, I can probably just move on and stop being an annoying "enthusiast."

 

[algirdas]

drill another hole for the pin through the receiver and draw bar, but towards front of bar to clear valance

 

[vandermic07]

not hard to cut/grind welds off but since you already cut the bumper cover, you might as well trim it some more or drill a new hole. alot easier than cutting off welds

 

[SFHGolfTDI]

not hard to cut/grind welds off but since you already cut the bumper cover, you might as well trim it some more or drill a new hole. alot easier than cutting off welds

Yes. Had a good look at everything last night and decided that was the most sane path. Painted the area behind the receiver matte black and need to cut the cover and install my wiring. It'll be fine. Thanks for the input everyone.

 

[SFHGolfTDI]

Here's how things ended up: http://forums.tdiclub.com/showpost.php?p=4828446&postcount=19